Photographic developer compositions



Patented Apr. 2, 1946 PATENT orrlce PHOTOGRAPHIC DEVELOPER COMPOSITIONS Robert 0. Lyon, New Brunswick, N. J assignor to E. I. du'Pont de Nemours & Company, Wilmington, Del., a. corporation 01' Delaware No Drawing. ,Application April 21, 1944, Serial No. 532,217

12 Claims.

This invention relates to new photographic developers. More specifically, the invention relates to photographic developer compositions including developing baths which contain ternary compounds as the developing agents.

It is known that ortho-phenylene-diamines, polyhydroxy-benzenes, and amino-phenols are three classesof compounds which are useful as photographic developing agents. Moreover, it is known that developing compositions may be made from mixtures of two agents or from addition compounds of two agents. For example, metal and hydroquinone are often used together. Also, the addition compound of para-phenylenediamine and pyrocatechol or-hydroquinone has been used in fine grain developers.

It is an object of this invention to provide new fine grain photographic developer compositions. Another object is to provide new photographic developer dry powder compositions. A further object is to provide new developing solutions and baths which may be readily prepared in high purity. A still further object is to provide photographic developerswhich endow photographic emulsions with wide exposure latitude. Other objects will appear hereinafter.

These objects have been accomplished by the discovery that certain ortho-phenylene-diamines combine in molecular proportions with polyhydroxy-benzenes and amino-phenols to form compounds which are easily crystallized in a state of high purity and which are exceptionally useful I as fine grain photographic developers in admixture with other Well known developer components. These compounds are true chemical compounds containing one or more molecules of each of the three components and should not be confused with condensation products formed by the elimination of parts of the components, as, for example, the elimination of water.

In order that the invention may be more fully understood, the following examples are given by way of illustration, although the invention is not limited thereto as will become more apparent hereinafter. In the examples, parts signify parts by weight.

ExAmrLnI orizing carbon. The mixture is heated to boiling 55 temperature and 1 part of sodium hydrosulfite is added. The hot mixture is filtered under vacuum. The filtrate is cooled to 10 C. and clear mixtures separate from the mother liquor. One

5 hundred and nine (109) parts 01 a crystalline product is recovered.

The mother liquor is concentrated and cooled with a recovery of 15 parts of additional crystals. The crystals of the ternary compounds having equimolecular proportions of ortho-phenylenediamine, pyrocatechol, and para-aminq-phenol have a meiting point of '73-74 C.

ExAMrLr II Twelve and two-tenths (12.2) parts of methyl 4-ortho-phenylene-diamine, 11.0 parts of pyrocatechol, and 10.9 parts of para-amino-phenoi are added to 230 parts of water, 1.5 parts oi a 37 per cent aqueous solution of sodium bisulfite and 1 part of decolorizing carbon. The mixture is heated until a solution of the first three materials mentioned is obtained and 1 part 0! sodium hydrosulfite is added. The hot mixture (100 C.) is filtered under vacuum and the filtrate is then cooled to 10 C. Twenty-eight and one-halt (28.5) parts of crystals having a melting point of 76-77" C. are recovered from the mother liquor. These are crystals of an equimolecular ternary compound of methyl-4-ortho-phenylene-diamine, pyrocatechol, and para-amino-phenol.

ExAurLr III hot mixture is filtered under vacuum. The filtrate is cooled and 20. 1 parts of crystals of an equimolecular ternary compound having'a melting point of Iii-77 C. are recovered.

EXMIPLI 1V Example III is repeated using, instead of solid chloro-4-ortho-phenylene-diamine,' a solution of 10.5 parts of this material in parts of ether. The ether is boiled of! during the heating of the mixture and the results are as in Example III.

Exunn v Eight and sixty-tour one-hundredths (8.64) parts of ortho-phenylene-diamine. 8.60 parts of pyrocatechol, and 4.32 parts of ortho-amino-phenol are dissolved in 100 parts of water having added thereto 2 parts of a, 30 per cent bisulfite so- EXAMPLE VI Twenty-one and six-tenths (21.6) parts of ortho-phenylene-diamine and 11.0 parts of hydroquinone are dissolved in 125 parts of water with the addition of 2 parts of a 30 per cent sodium bisulfite aqueous solution and 1 part of decolorizing carbon. The mixture is brought to boiling temperature and part of sodium hydrosulfite is added. The hot solution is filtered and the filtrate is cooled. Binary crystals of orthophenylene-diamine and hydroquinone having a melting point of 105.5-106 C. are recovered.

To sixteen and three-tenths (16.3) parts of this binary, there is added 5.45 parts of paraamino-phenol in 85 parts of water together with 1 part of a 'per cent sodium bisulfite and 2 parts of decolorizing carbon. The mixture is boiled and filtered while hot. The cooled filtrate yields crystals of the ternary compound having a melting point of 99.6-100.2 C. The mother liquor is concentrated and cooled to obtain a second crop of crystals. A total of 21 parts are recovered from the 21.75 parts of charge, the crystals from the two recoveries having substantially the same melting point.

EXAMPLE VII Twenty-one and six-tenths (21.6) parts of ortho-phenylene-diamine, 11.0 parts of hydroquinone, and 5.45 parts of ortho-amino-phenol are dissolved at boiling temperature in 190 parts of water to which is added 2. parts of a 30 ,per cent aqueous solution of sodium bisulfite and 2 parts of decolorizing carbon. One (1) part of sodium hydrosulfite is added and the hot solution is filtered. The filtrate is cooled and crystals of the ternary, melting at 103-103.5 C. is recovered. A mother liquor is concentrated and cooled to obtain a second crop of crystals. A total of 33 parts of the ternary are recovered from the 38.05 parts of the materials charged. This ternary contains the components in the molecular ratio of 4 mols of ortho-phenylene-diamine, 2 mols of hydroquinone, and 1 mol of ortho-amino-phenol.

EXAMPLE VIII Twenty-one and six-tenths (21.6) parts of ortho-phenylene-diamine, 25.2 parts of pyrogallol, and 10.9 parts of para-amine-phenol are dissolved in 100 parts of boiling water to which is added 1 part of a 30 per cent sodium bisulfite aqueous solution and 2 parts of decolorizing carbon. While this solution is boiling, /g part of sodium hydrosulfite is added and themixture is filtered. The filtrate is cooled and crystals having a melting point of 88.5-89.4? C. are recovered. These crystals are a ternary compound having their components in the molecular ratio oi 2 mols of ortho-phenylene-diamine, 2 mols of pyrogallol, and 1 mol of para-amino-phenol.

Emma: 1x

Ten and eight-tenths (10.8) parts of orthophenylene-diamine, 7.2 parts of chloro-hydroquinone, and 5.45 parts of para-amino-phenol are dissolved in 65 parts of water to which is added 1 part of a 30 per cent sodium bisulflte aqueous solution and 2 parts of decolorizing carbons. The solution is heated to boiling and part of sodium hydrosulfite is added. The hot solution is filtered and the filtrate is cooled. Crystals having a melting point of 75-76 C. are collected, which crystals area ternary composed of 2 mols of ortho-phenylene-diamine, 1 mol of chloro-hydroquinone, and 1 mol of para-amino-- phenol.

EXAMPLE X Example IX is repeated substituting 9.45 parts of bromo-hydroquinone for the 7.2 parts of chlorohydroquinone and crystals having a melting point of 85-87.8 C. are recovered.

EXAMPLE 1;;

Ten and eight-tenths (10.8) parts of orthophenylene-diamine, 15.8 parts of chloro-toluhydroquinone (4 chloro-1-methyl-2,5-hydroxybenzene), and 10.9 parts of para-amino-phenol are dissolved in 105 parts of water to which is added 2 parts of a 30 per cent solution of sodium bisulfite and 2 parts of decolorizing carbon. The solution is heated to boiling and 1 part of sodium hydrosulfite is added. The hot solution is filtered and the filtrate is cooled to 5 C. and the 34 parts of crystals of the ternary body are recovered. These crystals have a melting point of 118-119 C.

Not all ortho-phenylene-diamines are capable of forming the addition compounds. This invention includes ortho-phenylene-diamines of the formula:

NH: wherein R is hydrogen, halogen, or alkyl, e. g., methyl, ethyl, etc. Theunsubstituted orthophenylene-diamine and the 4-chloroand 4- methyl-compounds are preferred.

Polyhydroxy-benzenes suitable for use in the present invention include both unsubstituted and substituted compounds, such, for example, as hydroquinone, 2-hydroxyhydroquinone, pyrogallol, pyrocatechol, brornoand chloro-hydroquinone, 2:3-dichloroand dibromo-hydroquinone, chloro-tolu-hydroquinone, etc. Accordingly, a poly-hydroxy-benzene as used in this application, means a member of the group consisting of unsubstituted and substituted orthoand para-polyhydroxy-benzenes.

Both para-amino-phenols and ortho-aminophenols may be used as the third component, for example, 2 :4-diaminophenol, 4-chloro-2-methylaminophenol. Para-amino-phenol is preferred.

As is shown by the examples, the three components combine in molecular ratios of small whole numbers. Using a particular selection of three components,'there is only one ratio which solved in an organic solvent therefor and mixed in organic solvent solution with the other components in aqueous solution. The organic solvent protects the base from oxidation until the ternary body has been formed. This procedure is illustrated in Example IV.

In general, the components may be combined by heating in aqueous solution. However, the process is much improved by the presence of sodium bisulflte and, hence, the presence of this material is preferred. The decolorizing carbon used in the examples removes impurities. Where desirable, it may be omitted, especially when pure starting materials are used.

Where the formation of the ternary is difilcult, it is sometimes desirable to first form a binary and then add the third component. This is illustrated in Example VI. This procedure may be used whenever desired.

The new ternary compounds made according to the present invention, when used as photographic developing agents, produce very fine grain photographic images which, at the same time, are characterized by high speed.

The raw materials need not be of high purity since the process of making the addition compounds automatically removes practically all of the impurities during the crystallizing step.

The developing agents may be incorporated with the usual ingredients of dry photographic developing compositions and aqueous solutions and baths which are useful'with paraphenylenediamine or para-N-methyl amino-phenol, e. g., soluble sulfites and alkalies and restrainers, e. g., potassium bromide. For example, excellent results can be obtained by developing for 18 minutes at 20 0. with a bath of the following The above formula was prepared by admixing the solid ingredients with the water. With the ternary body of Example I and'the above formula,

the pH is 8.16. At this pH, there is good film 50 speed while maintaining fine grain. The chief characteristic of the H 8: D curve made by using this developer in this formula on a standard film is the long straight line portion of the curve. This makes for great latitude with varying exposures. especially with the long exposures. The ternary bodies of the present invention are of special value with high speed, negative types of silver halide emulsions. Such emulsions generally tend toward graininess which the present developers prevent. While it is true that characteristics of the H 82 D curve depend on the emulsion of the photographic material as well as on the developer, the characteristics of these new developers which make for a long straight line portion to the H 8: D curve, will still tend to be imposed on the H & D curve no matter what the emulsion. In other words, this particular effect is a characteristic of the developer and if the developer is usedwith an emulsion which already has a long straight line portion to its H 8: D curve, the latitude would still be greatly increased. If it is used with an emulsion that has not much latitude, the effect will not be as great, but still would be greater than if a standard developer 76 were used. dry state and diluted at the time of use.

One may get even greater film speed by using a developing formula of higher DH. For example,

if the ternary of Example I is used in the follow-v the pH is 8.8. This formula will give greater film 16 speed on. ultra speed films, especially if developmentis prolonged to 30 minutes or if the temperature is raised to 27-30 C. In general, if fine grain characteristics are desired, the pH of the developing bath should be kept around 8.2 or

20 lower. Dry mixtures, can be made by mixing the components or a small amount or water, e. g., 150 cc's., used for a concentrated developer which may be diluted for use.

In the above developer formulae, any alkali,

such, for example, as sodium carbonate, potassium carbonate, sodium hydroxide, trisodium phosphate, etc., may be substituted for the borax,

although borax is preferred. The amount olf sodium sulfite may be changed, and, if keeping qualities are not'desired, the sodium sulflte may be omitted. Potassium bromide may be added.

In general, it may be stated that the new agents may be substituted for the prior art reducing agents in known developer formulas, particularly fine grain developer formulas, with improved results in definition of the resulting image and with greatly increased latitude in exposure time of the silver halide during formation of the latent image.

The developing agents made according to the present invention are also useful in color-forming developers. For example, 4 grams of 2,4- dichloro-alpha-naphthol dissolved in sufilcient ethyl alcohol to make a clear solution is added to 4 the following formula:

Formula C Parts Ternary body of Example I 10 Sodium sulfite (anhydrous) 5 Sodium carbonate (anhydrous) 25 Water 1000' This developer, when used'upon an exposed silver halide emulsion produces, in addition to the silver image, a blue-green dye image. The silver image may be removed by any prior means, such as, for example. Farmer's reducer," leaving a clear dye image. By the use of other dye components, other colored images may be obtained. Other useful color-formers are described in the British Journal of Photography, October 7, 1938, pages 22'; to 629, and October 14, 1938, pages 647 and It is apparent that many widely diiferent embodiments of this invention may be made withmy co-pending application Serial No. 377,843

filed February 7, 194

I claim:

1. A process which comprises developing a silver halide latent image with a developer comprising the crystalline ternary addition compound The components can be mixed in a of each of the three compounds, a poly-hydroxyand a compound of the formula:

wherein R is a member of the group consisting of hydrogen, halogen, and alkyl, characterized in that said three compounds are present in molecular ratios of small whol numbers, said addition compound having a sharp melting point.

2. A process which comprises developing a silver halide latent image with an aqueous alkaline developer solution containing the crystalline ternary addition compound of each of the three compounds pyrocatechol, para-amino-phenol and para-chloro-ortho-phenylene-diamine in equal molecular proportions, said compound having a melting point of '76 to 77 C.

.3. A process which comprises developing asilver halide latent image with an aqueous alkaline nary addition compound of each of the three compounds hydroquinone, ortho-amino-phenol, and ortho-phenylenediamine in the molecular proportion 2:1:4, respectively, said addition compound having a melting point of 103 to 103.5 C.

4. A process which comprises developing a silver halide latent image with an aqueous alkaline developer solution containing the crystalline the formula:

I NR2 wherein R is a member of the group consistin of hydrogen, halogen, and alkyl, characterized in that said three compounds are present in molecular ratios of small whole numbers, said addition compound having a sharp melting point.

6. A photographic developing bath comprising water, an alkaline compound, and the crystalline ternary addition compound of each of th three compounds, pyrocatechol, para amino phenol I developer solution containing th crystalline terand para chloro orthophenylenediamine in equal molecular proportions, said compound having a melting point of 76 to 77 C.

7. A photographic developing bath comprising water, an alkaline compound, and the crystalline ternary addition compound of each of the three compounds hydroquinone, ortho-amino-phenol, and ortho-phenylenediamine in the molecular proportion 2:1:4, respectively, said addition compound having a melting point of 103 to 103.5 C.

8. A photographiodeveloping bath comprising water, an alkaline compound, and the crystalline ternary addition compound of each .of the three compounds chlorohydroquinone, para-aminophenol, and ortho-phenylenediamine in the molecular proportion of 1:1:2, respectively, said addition compound having a melting point of '75 to 76 C.

9. A dry developing composition comprising a water soluble sulfite, an alkaline compound and the crystalline ternary addition compound of each of the three compounds a poly-hydroxybenzene, a member of the group consisting of ortho-amino-phenols and para-amino-phenols, and a compound of the formula:

I|\III2 wherein R is a member of the group consisting of hydrogen, halogen, and alkyl, characterized in that said three compounds arepresent in molecular ratios of small whole numbers, said addition compound having a sharp melting point.

10. A dry developing composition comprising a water soluble sulfite, an alkaline compound, and the crystalline ternary addition compound of each of th three compounds pyrocatechol, para- .amino-phenol and para-chloro-ortho-phenylenediamine in equal molecular proportions, said compound having a melting point of 76 to 77 C.

11. A dry developing composition comprising a water soluble sulfite, an alkaline compound, and the crystalline ternary addition compound of each of the three compounds hydroquinone, ortho-amino-phenol, and ortho-phenylenediamine in the molecular proportion 2:1:4, respectively, said addition compound having a melting point of 103 to 103.5 C.

12.A dry developing composition comprising a water soluble sulfite, an alkaline compound, and the crystalline ternary addition compound of each of the three compounds chlorohydroquinone, paraamino-phenol, and ortho-phenylenediamine in the molecular proportion of 1:1:2, re-

spectively, said addition compound having a melting point of to '7 6 C.

ROBERT C. LYON. 

